AT89LS51 View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT89LS51

8-bit Low-Voltage Microcontroller with 4K Bytes In-System Programmable Flash

Atmel Corporation 

4.10 EA/VPP

4.11 XTAL1

4.12 XTAL2

External Access Enable. EA must be strapped to GND in order to enable the device to fetch

code from external program memory locations starting at 0000H up to FFFFH. Note, however,

that if lock bit 1 is programmed, EA will be internally latched on reset.

EA should be strapped to VCC for internal program executions.

This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming.

Input to the inverting oscillator amplifier and input to the internal clock operating circuit.

Output from the inverting oscillator amplifier

5. Special Function Registers

A map of the on-chip memory area called the Special Function Register (SFR) space is shown in

Table 5-1.

Note that not all of the addresses are occupied, and unoccupied addresses may not be imple-

mented on the chip. Read accesses to these addresses will in general return random data, and

write accesses will have an indeterminate effect.

6 AT89LS51

3053B–MICRO–3/05

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